Surround – Butyl RubberView larger Surround – Butyl Rubber Butyl Rubber is a synthetic (man made) material and is valued for its chemical inertness, impermeability to air, and ability to endure or resist exposure to the many types of weather fronts. Butyl rubber applications from sports equipment to automotive parts, the medical industry and more.It is used in the Surrounds that connect the cone to the basket. Did you know that most modern chewing gum uses food-grade butyl rubber as the central gum base, which contributes not only the gum's elasticity but an obstinate, sticky quality? Just like that chewing gum, the Butyl Rubber Surround in our speakers can take the equivalent amount of abuse without quitting on you. Specifications 12 inch 2200 Watt Dual Voice Coil SubwooferPower Handling (Peak): 2200WPower Handling (Continuous): 1100WSensitivity (1 Watt/1 Meter): 95dBImpedance: Dual 4 OhmVoice Coil: 2 inchMounting Depth: 5-1/4"Frequency Response: 28 Hz – 2.5 kHz Voice Coil – KaptonView larger Voice Coil – Kapton Until about 1970, all speaker voice coils were wound on paper tubes. The voice-coil is the part of the speaker that the output of the amplifier is directly fed to, and they get hot when driven hard. Unfortunately, paper has a nasty habit of burning up when it gets hot. As amps began to get drastically more powerful, Kapton, which remains stable up to about 725 degrees Fahrenheit, came along and fixed the heat problem. Kapton beats paper hands-down in all possible ways. It can be made thinner and stronger. It can take way more heat and mechanical stress, plus it has excellent dielectric properties. Cone – Poly InjectionView larger Cone – Poly Injection Polyurethane is a resilient, flexible and durable manufactured material that can take the place of paint, cotton, rubber, metal, or wood in thousands of applications across virtually all fields. It can be hard like fiberglass, squishy like upholstery foam, protective like varnish, bouncy like rubber, or sticky like glue. In the specific case of our cones, this material allows for maximum flexibility that produces great sounding speakers lasting you a long, long time.